1. Field of the Invention
The present invention relates to an extendable stick the length of which can be changed freely.
2. Description of the Prior Art
A stick is an aid for a walker, and is used for safety, for example, for the purpose of supporting the body of the walker. A stick is used mainly by elderly people or physically challenged people who have difficulty in walking normally, but a stick can also be used by hikers. As described above, a stick can be used for a variety of purposes, but a stick is usually a pole the length of which is unchanged.
Since a stick may give the user thereof excessive fatigue or even expose the user to danger when the length thereof is not appropriate for the user, it will be convenient if the length can be adjusted according to the user's height, or leg or arm length. That is, it will be convenient if a stick is so constituted that the length thereof can be changed to enable the stick to support the user's body appropriately. It will be even more convenient if the adjustment can be done infinitely and finely.
A stick that has a length-adjusting mechanism itself may be realized relatively easily by the application of the prior art. However, it is necessary that the adjustment be able to be done easily because the majority of users of a stick are elderly people or physically challenged people who have difficulty in walking normally. It is possible as an example of application of the prior art, to realize a stick which is so constituted that a thin pipe can slide in a thick pipe and that the pipes can be fixed to each other by means of pins or the like. However, with such constitution, it Is not easy to adjust the length.
The user may need a stick to support his body, not only when he walks but, for example, when he stands up, or when he goes upstairs or downstairs. Elderly people or physically challenged people who have difficulty in walking normally, need a stick more often than is expected. In order to use a stick in a variety of situations as described above, it is necessary that the length of a stick be able to be adjusted freely, and it is important that a stick be so constituted that the adjustment may be done easily.